Contra Costa County, California · Frost dates
Contra Costa County frost dates.
First-frost, last-frost, and growing-season length for Contra Costa County, California. Sourced from NOAA 1991-2020 Climate Normals.
Data confidence: high · USDA zone: 9b
32°F — light freeze
Last spring frost
- 10%
- 04-15
- 20%
- 04-05
- 50%
- 03-08
- 80%
- 01-31
- 90%
- 01-12
First fall frost
- 10%
- 11-23
- 20%
- 12-01
- 50%
- 12-22
- 80%
- 01-22
- 90%
- 02-11
28°F — killing freeze
Last spring freeze
- 10%
- 03-23
- 20%
- 03-03
- 50%
- 02-08
- 80%
- 01-04
- 90%
- 12-21
First fall freeze
- 10%
- 12-08
- 20%
- 12-20
- 50%
- 01-16
- 80%
- 02-22
- 90%
- 03-03
Growing season length (days, 28°F threshold)
- Short year
- 260
- Median
- 342
- Long year
- 437
Source NOAA station
MT DIABLO JUNCTION, CA US
3.0 mi · 30 yrs of record (1991–2020) · 2170 ft elev.
Data from MT DIABLO JUNCTION, CA US, 3 miles away with 30-year NOAA record (1991-2020).
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